This invention relates to an objective lens system of what may be called the expanded Tessar type, which type is disclosed, for example, in U.s. Pat. No. 2,105,799. The lens has a front member, designated in the drawing and in the examples as Vgl (standing for the German word Vorderglied) and a rear member designated as Hgl (standing for the German word Hinterglied). The front member is made up of three individually air spaced lens elements, and the rear member is a doublet consisting of two lens elements of opposite sign of power, cemented to each other to constitute a single component. A diaphragm space is provided between the front member and the rear member. The neighboring cemented surfaces of this doublet constituting the rear member constitute a collecting cement surface. In the front member, the front element is an unequal-sided collecting element, followed at a small finite air spacing by a positive meniscus which is convex toward the front and concave toward the rear, this meniscus being followed, in turn, by an unequal-sided negative lens which has its most strongly curved surface in the form of a surface concave toward the rear. A dispersing air lens is formed between the rear surface of the second element and the front surface of the negative lens constituting the third element.